Network Working Group G. Parsons
Request for Comments: 2306 Northern Telecom
Category: Informational J. Rafferty
Human Communications
March 1998
Network Working Group G. Parsons
Request for Comments: 2306 Northern Telecom
Category: Informational J. Rafferty
Human Communications
March 1998
Tag Image File Format (TIFF) - F Profile for Facsimile
标签图像文件格式（TIFF）-F传真配置文件
Status of this Memo
本备忘录的状况
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1998). All Rights Reserved.
版权所有（C）互联网协会（1998年）。版权所有。
Overview
概述
This document describes in detail the definition of TIFF-F that is used to store facsimile images. The TIFF-F encoding has been folklore with no standard reference definition before this document.
本文档详细描述了用于存储传真图像的TIFF-F的定义。TIFF-F编码是民间传说，在本文件之前没有标准参考定义。
Internet Fax Working Group
因特网传真工作组
This document is a product of the IETF Internet Fax Working Group. All comments on this document should be forwarded to the email distribution list at <ietf-fax@imc.org>.
本文件是IETF互联网传真工作组的产品。对本文件的所有评论应转发至<ietf-fax@imc.org>.
This document references the Tag Image File Format (TIFF) to define the F profile of TIFF for facsimile (TIFF-F) as a file format that may be used for the storage and interchange of facsimile images.
本文件参考标签图像文件格式（TIFF），将传真TIFF（TIFF-F）的F配置文件定义为可用于传真图像存储和交换的文件格式。
TIFF (Tag Image File Format) Revision 6.0 is defined in detail within [TIFF].
TIFF（标签图像文件格式）6.0版在[TIFF]中有详细定义。
A brief review of concepts used in TIFF is included in this document as background information, but the reader is directed to the original TIFF specification [TIFF] to obtain specific technical details.
本文档作为背景信息简要回顾了TIFF中使用的概念，但读者可参考原始TIFF规范[TIFF]，以获得具体的技术细节。
TIFF provides a method to describe and store raster image data. A primary goal of TIFF is to provide a rich environment within which implementations can exchange image data. [TIFF] characterizes Baseline TIFF as being the core of TIFF, the essentials that all mainstream TIFF developers should support in their products. Applications of TIFF are defined by using Baseline TIFF as a starting point and then defining "extensions" to TIFF that are used for the specific "application", as well as specifying any other differences from Baseline TIFF.
TIFF提供了一种描述和存储光栅图像数据的方法。TIFF的主要目标是提供一个丰富的环境，实现可以在其中交换图像数据。[TIFF]将基线TIFF描述为TIFF的核心，这是所有主流TIFF开发人员在其产品中应该支持的要素。TIFF应用程序的定义是以基准TIFF为起点，然后定义用于特定“应用程序”的TIFF“扩展”，并指定与基准TIFF的任何其他差异。
Though it has been in common usage for many years, TIFF-F has previously never been documented in the form of a standard. An informal TIFF-F document was originally created by a small group of fax experts led by Joe Campbell. The existence of TIFF-F is noted in [TIFF] but it is not defined. This document defines the F application of [TIFF]. For ease of reference, the term TIFF-F will be used throughout this document as a shorthand for "F Profile of TIFF for Facsimile". TIFF-F files are intended for use with the image/tiff MIME media content-type which includes support for the "application" parameter (e.g., application=faxbw).
尽管TIFF-F已经普遍使用多年，但此前从未以标准的形式记录。非正式的TIFF-F文档最初由Joe Campbell领导的一个传真专家小组创建。TIFF-F的存在在[TIFF]中有说明，但没有定义。本文件定义了[TIFF]的F应用。为便于参考，本文件中将使用术语TIFF-F作为“传真TIFF的F档案”的缩写。TIFF-F文件旨在与图像/TIFF MIME媒体内容类型一起使用，该类型包括对“应用程序”参数的支持（例如，application=faxbw）。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [REQ].
本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[REQ]中的说明进行解释。
Up until TIFF 6.0, TIFF supported various "Classes" which defined the use of TIFF for various applications. Classes were used to support specific applications and in this spirit, TIFF-F has been known historically as "TIFF Class F". Previous informal TIFF-F documents used the "Class F" terminology.
在TIFF 6.0之前，TIFF支持各种“类”，这些类定义了TIFF在各种应用程序中的使用。类用于支持特定的应用程序，本着这种精神，TIFF-F在历史上被称为“TIFF类F”。以前的非正式TIFF-F文件使用了“F类”术语。
As of TIFF 6.0 [TIFF], the TIFF Class concept has been eliminated in favor of the concept of Baseline TIFF. Therefore, this document updates the definition of TIFF-F as the F profile of TIFF for facsimile, by using Baseline TIFF as defined in [TIFF] as the starting point and then defining the differences from Baseline TIFF which apply for TIFF-F. In almost all cases, the resulting definition of TIFF-F fields and values remains consistent with those used historically in earlier definitions of TIFF Class F. Where some
自TIFF 6.0[TIFF]起，TIFF类别概念已被取消，取而代之的是基准TIFF的概念。因此，本文件将TIFF-F的定义更新为传真TIFF的F配置文件，使用[TIFF]中定义的基准TIFF作为起点，然后定义适用于TIFF-F的与基准TIFF的差异。在几乎所有情况下，TIFF-F字段和值的最终定义与先前TIFF F类定义中使用的定义保持一致。其中
of the values for fields have been updated to provide more precise conformance with the ITU-T [T.4] and [T.30] fax recommendations, these differences are noted.
为了更精确地符合ITU-T[T.4]和[T.30]传真建议，已更新了字段值中的一部分，注意到了这些差异。
The intent of this specification is to document:
本规范旨在记录：
1) The fields and values which are applicable for this F profile of TIFF for facsimile. 2) A minimum set of TIFF-F fields and values which should be able to interwork with virtually all historic TIFF-F readers. 3) A broader range of values for the traditional TIFF-F fields that will provide support for the most widely used facsimile compressions, page sizes and resolutions, consistent with the ITU-T [T.4] and [T.30] recommendations.
1) 适用于传真TIFF的F配置文件的字段和值。2） 至少一组TIFF-F字段和值，应能够与几乎所有历史TIFF-F读取器交互。3） 传统TIFF-F字段的范围更广，可支持最广泛使用的传真压缩、页面大小和分辨率，符合ITU-T[T.4]和[T.30]建议。
The structure of the TIFF-F definition will be as follows. A brief review of the structure of TIFF files and practical guidelines for the writing and reading of multi-page TIFF-F files is provided in sections 3.1.3 and 3.1.4.
TIFF-F定义的结构如下所示。第3.1.3节和第3.1.4节简要回顾了TIFF文件的结构以及多页TIFF-F文件的书写和阅读实用指南。
A review of TIFF-F fields follows. Section 3.2 reviews the fields from Baseline TIFF that are applicable for black and white (bi-level) images and are also used by TIFF-F.
下面对TIFF-F字段进行回顾。第3.2节回顾了基线TIFF中适用于黑白（二级）图像且TIFF-F也使用的字段。
Section 3.3 reviews the other required TIFF-F fields. Several fields that are specific extensions for TIFF-F are reviewed in section 3.4. There are also fields that may be helpful, but are not required. These recommended fields are listed in the section 3.5. Section 3.6 defines the requirements for the minimum subset of TIFF-F fields and values to maximize interoperability. Several technical topics, including implementation issues and warnings are discussed in subsequent sections. Finally, section 3.9 introduces the TIFF-F Reader and Writer. A table of the required and recommended fields for a TIFF-F Reader is provided, along with details on the permitted set of values.
第3.3节审查了其他所需的TIFF-F字段。第3.4节回顾了TIFF-F的几个特定扩展字段。还有一些字段可能有用，但不是必需的。第3.5节列出了这些推荐字段。第3.6节定义了TIFF-F字段和值的最小子集的要求，以最大限度地提高互操作性。几个技术主题，包括实现问题和警告，将在后续章节中讨论。最后，第3.9节介绍了TIFF-F读写器。提供了TIFF-F阅读器所需和推荐字段的表格，以及允许值集的详细信息。
The structure of TIFF files is specified within [TIFF]. In this section, a short summary of the TIFF structure is included for the informational purposes. In addition, some practical guidelines for the use of this structure in reading and writing TIFF-F files are addressed in the following section 3.1.4. The structure for writing "minimum subset" TIFF-F files is defined in section 3.6.2.
TIFF文件的结构在[TIFF]中指定。本节简要概述了TIFF结构，以供参考。此外，有关在读取和写入TIFF-F文件时使用此结构的一些实用指南，请参见以下第3.1.4节。第3.6.2节定义了编写“最小子集”TIFF-F文件的结构。
A TIFF file begins with an 8-byte image file header that defines the byte order used within a file (see section 3.9.1), includes a magic number sequence that identifies the content as a TIFF file, and then uses an offset to point to the first Image File Directory (IFD). An IFD is a sequence of tagged fields, sorted in ascending order (by tag value), that contains attributes of an image and pointers to the image data. TIFF fields (also called entries) contain a tag, its type (e.g. short, long, rational, etc.), a count (which indicates the number of values/offsets) and a value/offset. However, the actual value for the field will only be present if it fits into 4 bytes; otherwise, an offset will be used to point to the location of the data associated with the field. In turn, this offset may itself be used to point to an array of offsets.
TIFF文件以一个8字节的图像文件头开始，该头定义了文件中使用的字节顺序（见第3.9.1节），包括一个将内容标识为TIFF文件的幻数序列，然后使用偏移量指向第一个图像文件目录（IFD）。IFD是一系列标记字段，按升序（按标记值）排序，其中包含图像属性和指向图像数据的指针。TIFF字段（也称为条目）包含一个标记、其类型（例如短、长、有理等）、计数（指示值/偏移量的数量）和值/偏移量。但是，字段的实际值只有在符合4个字节时才会出现；否则，将使用偏移量指向与字段关联的数据的位置。反过来，此偏移本身可用于指向偏移数组。
For the case of facsimile data, many documents consist of a series of multiple pages. Within TIFF, these may be represented using more than one IFD within the TIFF file. Each IFD defines a subfile whose type is given in the NewSubfileType field. For the case of facsimile data that is placed in a TIFF-F file, each facsimile page in a multi-page document has its own IFD. For bi- level facsimile files, multiple IFDs are organized as a linked list, with the last entry in each IFD pointing to the next IFD (the pointer in the last IFD is 0). (There is also another technique for organizing multiple IFDs as a tree, that uses the SubIFDs field, but this technique is not applicable for TIFF-F images.) Within each IFD, the location of the related image data is defined by using fields that are associated with strips. These fields identify the size of strips (in rows), the number of bytes per strip after compression and a strip offset, which is used to point to the actual location of the image strip.
对于传真数据，许多文档由一系列多页组成。在TIFF中，可以使用TIFF文件中的多个IFD来表示。每个IFD定义一个子文件，其类型在NewSubfileType字段中给出。对于放置在TIFF-F文件中的传真数据，多页文档中的每个传真页都有自己的IFD。对于双层传真文件，多个IFD组织为一个链表，每个IFD中的最后一个条目指向下一个IFD（最后一个IFD中的指针为0）。（还有另一种将多个IFD组织为一棵树的技术，它使用SubIFDs字段，但该技术不适用于TIFF-F图像。）在每个IFD中，相关图像数据的位置通过使用与条带关联的字段来定义。这些字段标识条带的大小（以行为单位）、压缩后每个条带的字节数以及条带偏移量，该偏移量用于指向图像条带的实际位置。
TIFF has a very flexible file structure, but the use of some practical guidelines for implementors when writing multi-page TIFF-F files can produce TIFF structures which are easier for readers to process. This is especially for implementations in environments such as facsimile terminals where a complex file structure is difficult to support.
TIFF具有非常灵活的文件结构，但在编写多页TIFF-F文件时使用一些实用的指导原则，可以生成TIFF结构，使读者更易于处理。这尤其适用于难以支持复杂文件结构的环境（如传真终端）中的实现。
Traditionally, historical TIFF-F has required readers and writers to be able to handle multi-page TIFF-F files. Based on the experience of various TIFF-F implementors, it has been seen that the implementation of TIFF-F can be greatly simplified if certain practical guidelines are followed when writing multi-page TIFF-F files. However, for interchange robustness, TIFF-F readers SHOULD be prepared to read TIFF files whose structure is consistent with [TIFF], which supports a more flexible file structure than is recommended here.
传统上，历史TIFF-F要求读写器能够处理多页TIFF-F文件。根据各种TIFF-F实现者的经验，可以看出，如果在编写多页TIFF-F文件时遵循某些实用指南，TIFF-F的实现可以大大简化。但是，为了保证交换健壮性，TIFF-F读取器应该准备好读取结构与[TIFF]一致的TIFF文件，后者支持比此处推荐的更灵活的文件结构。
The structure for a multi-page TIFF-F file will include one IFD per page of the document. Therefore, each IFD will define the attributes for a single page. For simplicity, the writer of TIFF- F files SHOULD present IFDs in the same order as the actual sequence of pages. (The pages are numbered within TIFF-F beginning with page 0 as the first page and then ascending (i.e. 0, 1, 2,...). However, as noted in section 3.1.3, any field values over 4 bytes will be stored separately from the IFD. TIFF-F readers SHOULD expect IFDs to be presented in page order, but be able to handle exceptions.
多页TIFF-F文件的结构将包括每页文档的一个IFD。因此，每个IFD将定义单个页面的属性。为简单起见，TIFF-F文件的编写者应该按照与实际页面序列相同的顺序呈现IFD。（页面在TIFF-F中编号，从第0页开始作为第一页，然后升序（即0、1、2…）。但是，如第3.1.3节所述，任何超过4字节的字段值都将与IFD分开存储。TIFF-F阅读器应希望IFD按页面顺序显示，但能够处理异常。
Per [TIFF], the exact placement of image data is not specified. However, the strip offsets for each strip of image are defined from within each IFD. Where possible, a second simplifying assumption for the writing of TIFF-F files is to specify that the image data for each page of a multi-page document SHOULD be contained within a single strip (i.e. one image strip per fax page). The use of a single image strip per page is very useful for implementations such as store and forward messaging, where the file is usually prepared in advance of the transmission, but other assumptions may apply for the size of the image strip for implementations which require the use of "streaming" techniques (see section 3.7.6). In the event a different image strip size assumption has been used (e.g. constant size for image strips which may be less than the page size), this will immediately be evident from the values/offsets of the fields that are related to strips. From the TIFF-F reader standpoint, one image strip per page permits the image data to be found through reference via a single offset, resulting in a much simplified image structure and faster processing.
根据[TIFF]，未指定图像数据的确切位置。但是，每个图像条带的条带偏移是从每个IFD中定义的。在可能的情况下，TIFF-F文件写入的第二个简化假设是指定多页文档每页的图像数据应包含在单个条带中（即，每个传真页一个图像条带）。每页使用一个图像条对于存储和转发消息等实现非常有用，其中文件通常在传输之前准备好，但对于需要使用“流”技术的实现，其他假设可能适用于图像条的大小（见第3.7.6节）。如果使用了不同的图像条尺寸假设（例如，图像条的恒定尺寸可能小于页面尺寸），这将立即从与条带相关的字段的值/偏移中表现出来。从TIFF-F阅读器的角度来看，每页一个图像条允许通过单个偏移量通过引用找到图像数据，从而大大简化了图像结构并加快了处理速度。
A third simplifying assumption is that each IFD SHOULD be placed in the TIFF-F file structure at a point which precedes the image which the IFD describes. If any long field values are present (see section 3.1.3) then these SHOULD be placed after their referencing IFD and before the image data they describe.
第三个简化的假设是，每个IFD都应该放置在TIFF-F文件结构中IFD描述的图像之前的某个点上。如果存在任何长字段值（见第3.1.3节），则应将其放置在参考IFD之后，并放置在其描述的图像数据之前。
A fourth simplifying assumption for TIFF-F writers and readers is to place the actual image data in a physical order within the TIFF file structure which is consistent with the logical page order. In practice, TIFF-F readers will need to use the strip offsets to find the exact physical location of the image data, whether or not it is presented in logical page order.
TIFF-F编写器和读取器的第四个简化假设是将实际图像数据按物理顺序放置在TIFF文件结构中，该文件结构与逻辑页面顺序一致。在实践中，TIFF-F阅读器需要使用条带偏移来查找图像数据的确切物理位置，无论它是否以逻辑页面顺序显示。
TIFF-F writers MAY make a fifth simplifying assumption, in which the IFD, the value data and the image data for which the IFD has offsets precede the next image IFD. These elements MUST precede the next image IFD in the minimum set TIFF-F files (see section 3.6.2). However, this principle has been relaxed in the case of TIFF-F to reflect past practices.
TIFF-F编写器可以进行第五个简化假设，其中IFD、值数据和IFD具有偏移的图像数据先于下一个图像IFD。这些元素必须位于最小设置TIFF-F文件中的下一个图像IFD之前（见第3.6.2节）。然而，在TIFF-F的案例中，这一原则已经放宽，以反映过去的做法。
So, a TIFF-F file which is structured using the guidelines of this section will essentially be composed of a linked list of IFDs, presented in ascending page order, which in turn each point to a single page of image data (one strip per page), where the pages of image data are also placed in a logical page order within the TIFF-F file structure. (The pages of image data may themselves be stored in a contiguous manner, at the option of the implementor).
因此，使用本节指南构建的TIFF-F文件基本上由IFD链表组成，按升序排列，每个IFD链表依次指向一页图像数据（每页一条），其中图像数据页在TIFF-F文件结构中也按逻辑页面顺序排列。（根据实施者的选择，图像数据的页面本身可以以连续的方式存储）。
Baseline TIFF per [TIFF] requires that the following fields be present for all BiLevel Images: ImageWidth, ImageLength, Compression, PhotometricInterpretation, StripOffsets, RowsPerStrip, StripByteCounts, XResolution, YResolution and ResolutionUnit. TIFF-F uses all of these fields, but in some cases specifies a different range of acceptable values than Baseline TIFF. Per [TIFF], if fields are omitted, the Baseline TIFF default value(if specified) will apply.
基线TIFF per[TIFF]要求所有两层图像都存在以下字段：图像宽度、图像长度、压缩、光度测量解释、条纹偏移、行分割、条纹字节数、X分辨率、Y分辨率和分辨率单元。TIFF-F使用所有这些字段，但在某些情况下，指定的可接受值范围与基线TIFF不同。根据[TIFF]，如果省略字段，将应用基线TIFF默认值（如果指定）。
In the field definitions which follow in this section and subsequent sections, the fields will be presented in the following form:
在本节和后续章节中的字段定义中，字段将以以下形式显示：
Fieldname (tag-number) = values (if applicable). TYPE
Fieldname（标记号）=值（如果适用）。类型
A brief summary of the Baseline TIFF fields and their use in TIFF-F follows:
基线TIFF字段及其在TIFF-F中的使用简要概述如下：
ImageWidth(256) = 1728, 2048, 2432, 2592, 3072, 3648, 3456, 4096, 4864. SHORT or LONG. These are the fixed page widths in pixels. The permissible values are dependent upon X and Y resolutions as shown in sections 2 and 3 of [T.4] and reproduced here for convenience:
图像宽度（256）=172820482432259230723648345640964864。短或长。这些是以像素为单位的固定页面宽度。允许值取决于[T.4]第2节和第3节所示的X和Y分辨率，为方便起见，在此复制：
XResolution x Yresolution | ImageWidth
--------------------------------------------|------------------
204x98, 204x196, 204x391, 200x100, 200x200 | 1728, 2048, 2432
300x300 | 2592, 3072, 3648
408x391, 400x400 | 3456, 4096, 4864
--------------------------------------------|------------------
XResolution x Yresolution | ImageWidth
--------------------------------------------|------------------
204x98, 204x196, 204x391, 200x100, 200x200 | 1728, 2048, 2432
300x300 | 2592, 3072, 3648
408x391, 400x400 | 3456, 4096, 4864
--------------------------------------------|------------------
Historical TIFF-F did not include support for the following widths related to higher resolutions: 2592, 3072, 3648, 3456, 4096 and 4864. Historical TIFF-F documents also included the following values related to A5 and A6 widths: 816 and 1216. Per the most recent version of [T.4], A5 and A6 documents are no
历史TIFF-F不支持以下与更高分辨率相关的宽度：2592、3072、3648、3456、4096和4864。历史TIFF-F文件还包括以下与A5和A6宽度相关的值：816和1216。根据[T.4]的最新版本，A5和A6文件没有
longer supported in Group 3 facsimile, so the related width values are now obsolete. See section 3.8.2 for more information on inch/metric equivalencies and other implementation details.
第3组传真中不再支持，因此相关的宽度值现在已过时。有关英寸/公制当量和其他实施细节的更多信息，请参见第3.8.2节。
ImageLength (257). SHORT or LONG. LONG recommended. The total number of scan lines in the image.
图像长度（257）。短或长。长期推荐。图像中扫描行的总数。
Compression (259) = 3,4. SHORT. This is a required TIFF-F field. The permitted values for TIFF-F purposes are 3 and 4 as shown. The default value per Baseline TIFF is 1 (Uncompressed), but this value is invalid for facsimile images. Baseline TIFF also permits use of value 2 (Modified Huffman encoding), but the data is presented in a form which does not contain EOLs. Instead, TIFF-F specifies the value 3 for encoding one-dimensional T.4 Modified Huffman or 2-dimensional Modified READ data. The detailed settings which apply for T.4 encoded data are specified using the T4Options field. TIFF-F also permits use of the value 4 for the compression field, which indicates that the data is coded using a [T.6] compression method (i.e the Modified Modified READ two-dimensional method). The detailed settings which apply for T.6 encoded data are specified using the T6Options field.
压缩（259）=3,4。短的这是必需的TIFF-F字段。TIFF-F用途的允许值为3和4，如图所示。每个基线TIFF的默认值为1（未压缩），但此值对于传真图像无效。基线TIFF也允许使用值2（修改的哈夫曼编码），但数据以不包含EOL的形式呈现。相反，TIFF-F指定用于编码一维T.4修改的哈夫曼或二维修改的读取数据的值3。使用T4Options字段指定适用于T.4编码数据的详细设置。TIFF-F还允许对压缩字段使用值4，这表明数据是使用[T.6]压缩方法（即修改的读取二维方法）编码的。使用T6Options字段指定适用于T.6编码数据的详细设置。
Please refer to the definitions of the T4Options and T6Options fields in section 3.3, and section 3.8 for more information on the encoding of images and conventions used within TIFF-F.
有关TIFF-F中使用的图像编码和约定的更多信息，请参考第3.3节和第3.8节中T4选项和T6选项字段的定义。
PhotometricInterpretation (260) = 0,1. SHORT. This field allows notation of an inverted ("negative") image: 0 = normal 1 = inverted
光度解释（260）=0,1。短的此字段允许反转（“负片”）图像的表示法：0=正常1=反转
StripOffsets (273). SHORT or LONG. For each strip, the offset of that strip. The offset is measured from the beginning of the file. If a page is expressed as one large strip, there is one such entry per page.
条纹偏移（273）。短或长。对于每个条带，该条带的偏移量。偏移量是从文件的开头开始测量的。如果一个页面表示为一个大条带，则每页有一个这样的条目。
RowsPerStrip (278). SHORT or LONG. LONG recommended. The number of scan lines per strip. When a page is expressed as one large strip, this is the same as the ImageLength field.
RowsPerStrip（278）。短或长。长期推荐。每个条带的扫描线数。当页面表示为一个大条带时，这与ImageLength字段相同。
StripByteCounts (279). LONG or SHORT. LONG recommended. For each strip, the number of bytes in that strip. If a page is expressed as one large strip, this is the total number of bytes in the page after compression. Note that the choice of LONG or SHORT depends upon the size of the strip.
条带字节数（279）。长或短。长期推荐。对于每个条带，该条带中的字节数。如果页面表示为一个大条带，则这是压缩后页面中的总字节数。请注意，长短的选择取决于钢带的尺寸。
ResolutionUnit (296) = 2,3. SHORT. The units of measure for resolution: 2 = Inch 3 = Centimeter
分辨率单位（296）=2,3。短的分辨率的测量单位：2=英寸3=厘米
TIFF-F has traditionally used inch based measures.
TIFF-F传统上使用英寸测量。
XResolution (282) = 204, 200, 300, 400, 408 (inches). RATIONAL. The horizontal resolution of the TIFF-F image expressed in pixels per resolution unit. The values of 200 and 408 have been added to the historical TIFF-F values, for consistency with [T.30]. Some existing TIFF-F implementations may also support values of 77 (cm). See section 3.8.2 for more information on inch/metric equivalencies and other implementation details.
分辨率（282）=204200300400408（英寸）。合理的TIFF-F图像的水平分辨率，以像素/分辨率单位表示。200和408的值已添加到历史TIFF-F值中，以与[T.30]保持一致。一些现有的TIFF-F实现也可能支持77（cm）的值。有关英寸/公制当量和其他实施细节的更多信息，请参见第3.8.2节。
YResolution (283) = 98, 196, 100, 200, 300, 391, 400 (inches). RATIONAL. The vertical resolution of the TIFF-F image expressed in pixels per resolution unit. The values of 100, 200, and 391 have been added to the historical TIFF-F values, for consistency with [T.30]. Some existing TIFF-F implementations may also support values of 77, 38.5 (cm). See section 3.8.2 for more information on inch/metric equivalencies and other implementation details.
Y分辨率（283）=98196100200300391400（英寸）。合理的TIFF-F图像的垂直分辨率，以像素/分辨率单位表示。100、200和391的值已添加到历史TIFF-F值中，以与[T.30]保持一致。一些现有的TIFF-F实现也可能支持77,38.5（cm）的值。有关英寸/公制当量和其他实施细节的更多信息，请参见第3.8.2节。
In addition to the Baseline TIFF fields, there are additional required fields for TIFF-F. A review of the additional required fields for TIFF-F follows:
除基准TIFF字段外，TIFF-F还有其他必填字段。对TIFF-F其他必填字段的审查如下：
BitsPerSample (258) = 1. SHORT. Since TIFF-F is only used for black-and-white facsimile images, the value is 1 (the default) for all files.
比特采样（258）=1。短的由于TIFF-F仅用于黑白传真图像，因此所有文件的值均为1（默认值）。
FillOrder (266) = 1, 2. SHORT. TIFF F readers must be able to read data in both bit orders, but the vast majority of facsimile products store data LSB first, exactly as it appears on the telephone line. 1 = Most Significant Bit first. 2 = Least Significant Bit first.
填充顺序（266）=1，2。短的TIFF F阅读器必须能够以两种位顺序读取数据，但绝大多数传真产品首先存储LSB数据，与电话线上显示的数据完全相同。1=第一个最高有效位。2=最低有效位优先。
NewSubFileType (254)= (Bit 1 = 1). LONG.
This field is made up of 32 flag bits. Unused bits are
expected to be 0 and bit 0 is the low order bit. Bit 0 is set
to 0 for TIFF-F. Bit 1 is always set to 1 for TIFF-F,
indicating a single page of a multi-page image. The same bit
NewSubFileType (254)= (Bit 1 = 1). LONG.
This field is made up of 32 flag bits. Unused bits are
expected to be 0 and bit 0 is the low order bit. Bit 0 is set
to 0 for TIFF-F. Bit 1 is always set to 1 for TIFF-F,
indicating a single page of a multi-page image. The same bit
settings are used when TIFF-F is used for a one page fax image. See sections 3.1.1 and 3.1.2 for more details on the structure of multi-page TIFF-F image files.
当TIFF-F用于一页传真图像时，使用设置。有关多页TIFF-F图像文件结构的更多详细信息，请参见第3.1.1节和第3.1.2节。
PageNumber (297). SHORT/SHORT. This field specifies the page numbers in the fax document. The field comprises two SHORT values: the first value is the page number, the second is the total number of pages. Single-page documents therefore use 0000/0001 hex. If the second value is 0, the total number of pages in the document is not available.
页码（297）。短/短。此字段指定传真文档中的页码。该字段包含两个短值：第一个值是页码，第二个值是总页数。因此，单页文档使用0000/0001十六进制。如果第二个值为0，则文档中的总页数不可用。
SamplesPerPixel (277) = 1. SHORT. The value of 1 denotes a bi-level, grayscale, or palette color image.
采样每像素（277）=1。短的值1表示双层、灰度或调色板颜色图像。
There is also a requirement to include either the T4Options or the T6Options field in a TIFF-F IFD, depending upon the setting of the Compression field. These fields are defined in the next section on TIFF extensions.
根据压缩字段的设置，TIFF-F IFD中还需要包含T4选项或T6选项字段。这些字段将在关于TIFF扩展的下一节中定义。
These are fields which are extensions beyond the required TIFF-F fields. The following fields have been defined as extensions in [TIFF].
这些字段是所需TIFF-F字段之外的扩展。以下字段已在[TIFF]中定义为扩展。
T4Options (292) (Bit 0 = 0 or 1, Bit 1 = 0, Bit 2 = 0 or 1). LONG. This field is required if the value for the compression field has been set to 3. The values are set as shown below for TIFF-F. For TIFF-F, uncompressed data is not allowed and EOLs MAY be byte aligned (see section 3.8.3). bit 0 = 0 for 1-Dimensional, 1 for 2-Dimensional (MR) bit 1 = must be 0 (uncompressed data not allowed) bit 2 = 0 for non-byte-aligned EOLs or 1 for byte-aligned EOLs
T4选项（292）（位0=0或1，位1=0，位2=0或1）。长的如果压缩字段的值已设置为3，则此字段是必需的。TIFF-F的值设置如下所示。对于TIFF-F，不允许未压缩的数据，并且EOL可以是字节对齐的（参见第3.8.3节）。位0=0表示一维，1表示二维（MR）位1=必须为0（不允许未压缩数据）位2=0表示非字节对齐的EOL或1表示字节对齐的EOL
This field is made up of a set of 32 flag bits. Unused bits must be set to 0. Bit 0 is the low order bit. Please note that T4Options was known as G3Options in earlier versions of TIFF and TIFF-F. The data in a TIFF-F image encoded using one of the T.4 methods is not terminated with an RTC (see section 3.8.5).
该字段由一组32个标志位组成。未使用的位必须设置为0。位0是低阶位。请注意，T4选项在TIFF和TIFF-F的早期版本中被称为G3选项。使用T.4方法之一编码的TIFF-F图像中的数据不以RTC终止（见第3.8.5节）。
T6Options (293) = (Bit 0 = 0, Bit 1 = 0) LONG.
This field is required for TIFF-F if value of the compression
field has been set to 4. The value for this field is made up of
a set of 32 flag bits. Setting bit 0 to 0 indicates that the
data is compressed using the Modified Modified READ (MMR) two-
T6Options (293) = (Bit 0 = 0, Bit 1 = 0) LONG.
This field is required for TIFF-F if value of the compression
field has been set to 4. The value for this field is made up of
a set of 32 flag bits. Setting bit 0 to 0 indicates that the
data is compressed using the Modified Modified READ (MMR) two-
dimensional compression method. MMR compressed Data is two-dimensional and does not use EOLs. Each MMR encoded image MUST include an "end-of-facsimile-block" (EOFB) code at the end of each coded strip (see section 3.8.6). Uncompressed data is not applicable for bi-level facsimile images, so that bit 1 must be set to 0. Unused bits must be set to 0. Bit 0 is the low-order bit. The default value is 0 (all bits 0). bit 0 = 0 for 2-Dimensional bit 1 = must be 0 (uncompressed data not allowed)
三维压缩法。MMR压缩数据是二维的，不使用EOL。每个MMR编码图像必须在每个编码带的末端包含“传真块末端”（EOFB）代码（见第3.8.6节）。未压缩数据不适用于双层传真图像，因此位1必须设置为0。未使用的位必须设置为0。位0是低阶位。默认值为0（所有位均为0）。二维位1=的位0=0必须为0（不允许未压缩数据）
In earlier versions of TIFF, this field was named Group4Options. The significance has not changed and the present definition is compatible.
在TIFF的早期版本中，此字段名为Group4Options。重要性没有改变，目前的定义是一致的。
In addition, three new fields, defined as TIFF-F extensions, describe page quality. The information contained in these fields is usually obtained from receiving facsimile hardware (if applicable). These fields are optional. They SHOULD NOT be used in writing TIFF-F files for facsimile image data that is error corrected or otherwise guaranteed not to have coding errors.
此外，定义为TIFF-F扩展的三个新字段描述页面质量。这些字段中包含的信息通常从接收传真硬件（如适用）获得。这些字段是可选的。对于已纠正错误或以其他方式保证没有编码错误的传真图像数据，不应在写入TIFF-F文件时使用它们。
Some implementations need to understand exactly the error content of the data. For example, a CAD program might wish to verify that a file has a low error level before importing it into a high- accuracy document. Because Group 3 facsimile devices do not necessarily perform error correction on the image data, the quality of a received page must be inferred from the pixel count of decoded scan lines. A "good" scan line is defined as a line that, when decoded, contains the correct number of pixels. Conversely, a "bad" scan line is defined as a line that, when decoded, comprises an incorrect number of pixels.
有些实现需要准确地理解数据的错误内容。例如，CAD程序可能希望在将文件导入高精度文档之前验证文件的错误级别是否较低。由于第3组传真设备不必对图像数据执行纠错，因此必须从解码扫描线的像素计数推断接收页面的质量。“良好”扫描线定义为解码时包含正确像素数的线。相反，“坏”扫描线被定义为解码时包含不正确数量像素的线。
BadFaxLines (326). SHORT or LONG This field reports the number of scan lines with an incorrect number of pixels encountered by the facsimile during reception (but not necessarily in the file).
BadFaxLines（326）。短或长此字段报告传真机在接收期间（但不一定在文件中）遇到的像素数不正确的扫描行数。
Note: PercentBad = (BadFaxLines/ImageLength) * 100
Note: PercentBad = (BadFaxLines/ImageLength) * 100
CleanFaxData (327). SHORT N = 0 = Data contains no lines with incorrect pixel counts or regenerated lines (i.e., computer generated) 1 = Lines with an incorrect pixel count were regenerated by receiving device
清洁传真数据（327）。SHORT N=0=数据不包含像素计数不正确的行或重新生成的行（即计算机生成的行）1=接收设备重新生成像素计数不正确的行
2 = Lines with an incorrect pixel count are in the data and were not regenerated by receiving device (i.e. data contains bad scan lines)
2=数据中存在像素计数不正确的行，且接收设备未重新生成该行（即数据包含错误的扫描行）
Many facsimile devices do not actually output bad lines. Instead, the previous good line is repeated in place of a bad line. Although this substitution, known as line regeneration, results in a visual improvement to the image, the data is nevertheless corrupted. The CleanFaxData field describes the error content of the data. That is, when the BadFaxLines and ImageLength fields indicate that the facsimile device encountered lines with an incorrect number of pixels during reception, the CleanFaxData field indicates whether these bad lines are actually still in the data or if the receiving facsimile device replaced them with regenerated lines.
许多传真设备实际上并不输出坏线路。相反，将重复上一个好的行而不是坏的行。尽管这种替换（称为线再生）可以改善图像的视觉效果，但数据仍然被破坏。CleanFaxData字段描述数据的错误内容。也就是说，当BadFaxLines和ImageLength字段指示传真设备在接收期间遇到像素数不正确的行时，CleanFaxData字段指示这些坏行实际上是否仍在数据中，或者接收传真设备是否用重新生成的行替换它们。
ConsecutiveBadFaxLines (328). LONG or SHORT. This field reports the maximum number of consecutive lines containing an incorrect number of pixels encountered by the facsimile device during reception (but not necessarily in the file).
连续的传真线（328）。长或短。此字段报告传真设备在接收期间（但不一定在文件中）遇到的包含不正确像素数的最大连续行数。
The BadFaxLines and ImageLength data indicate only the quantity of such lines. The ConsecutiveBadFaxLines field is an indicator of their distribution and may therefore be a better general indicator of perceived image quality.
BadFaxLines和ImageLength数据仅指示此类行的数量。ConcertiveBadFaxlines字段是其分布的指示器，因此可能是感知图像质量的更好的通用指示器。
hese are fields that MAY be used in encoding TIFF-F files, but are ptional in nature and may be ignored by many TIFF readers. These ields are called recommended consistent with historical TIFF-F ractice.
这些字段可用于编码TIFF-F文件，但本质上是可选的，可能会被许多TIFF阅读器忽略。这些IELD被称为与历史TIFF-F实践一致的推荐IELD。
BadFaxLines (326) [defined in section 3.4]
BadFaxLines（326）[定义见第3.4节]
CleanFaxData (327) [defined in section 3.4]
CleanFaxData（327）[定义见第3.4节]
ConsecutiveBadFaxLines (328) [defined in section 3.4]
连续BadFaxLines（328）[定义见第3.4节]
DateTime (306). ASCII. Date and time in the format YYYY:MM:DD HH:MM:SS, in 24-hour format. String length including NUL byte is 20 bytes. Space between DD and HH.
日期时间（306）。ASCII码。日期和时间格式为YYYY:MM:DD HH:MM:SS，24小时格式。包含NUL字节的字符串长度为20字节。DD和HH之间的空间。
DocumentName (269). ASCII. This is the name of the document from which the document was scanned.
文件名（269）。ASCII码。这是扫描文档的文档的名称。
ImageDescription (270). ASCII. This is an ASCII string describing the contents of the image.
图像描述（270）。ASCII码。这是一个描述图像内容的ASCII字符串。
Orientation (274). SHORT. This field is designated as "Recommended" for consistency with historical TIFF-F, but is also a Baseline TIFF field with a default value of 1 per [TIFF]. The default value of 1 applies if the field is omitted, but for clarity, TIFF-F writers SHOULD include this field. This field might be useful for displayers that always want to show the same orientation, regardless of the image. The default value of 1 is "0th row is visual top of image, and 0th column is the visual left." An 180-degree rotation is 3. See [TIFF] for an explanation of other values.
方向（274）。短的为了与历史TIFF-F保持一致，此字段被指定为“推荐”，但也是一个基线TIFF字段，默认值为1 per[TIFF]。如果省略该字段，则默认值1适用，但为清楚起见，TIFF-F编写器应包括该字段。对于始终希望显示相同方向的显示器（无论图像如何），此字段可能很有用。默认值1为“第0行为图像的可视顶部，第0列为可视左侧”。180度旋转为3。有关其他值的说明，请参见[TIFF]。
Software (305). ASCII. The optional name and release number of the software package that created the image.
软件（305）。ASCII码。创建映像的软件包的可选名称和版本号。
This section defines the requirements for a minimum subset of TIFF-F fields and values that all TIFF-F readers SHOULD support to maximize interoperability with current and historical TIFF-F implementations. The TIFF-F structure for writing minimum subset files is also defined.
本节定义了所有TIFF-F阅读器应支持的TIFF-F字段和值的最小子集的要求，以最大限度地提高与当前和历史TIFF-F实施的互操作性。还定义了用于写入最小子集文件的TIFF-F结构。
A summary of the minimum subset TIFF-F fields and values is provided in the following table. The required fields for the minimum subset are shown under the column labeled "Field". The values for these fields in the minimum subset are shown under the column labeled "Minimum".
下表提供了最小子集TIFF-F字段和值的摘要。最小子集所需的字段显示在标有“字段”的列下。最小子集中这些字段的值显示在标记为“最小”的列下。
Field | Minimum | Comment
------------------|--------------|-------------------------------
BitsPerSample | 1 |one bit per sample
Compression | 3 |3 for T.4 (MH)
FillOrder | 2 |LSB first
ImageWidth | 1728 |
ImageLength | |required
NewSubFileType | Bit 1 = 1 |single page of multipage file
PageNumber | X/X |pg/tot, 0 base, tot in 1st IFD
PhotometricInterp | 0 |0 is white
ResolutionUnit | 2 |inches (default)
RowsPerStrip |=ImageLength |
SamplesPerPixel | 1 |one sample per pixel
Field | Minimum | Comment
------------------|--------------|-------------------------------
BitsPerSample | 1 |one bit per sample
Compression | 3 |3 for T.4 (MH)
FillOrder | 2 |LSB first
ImageWidth | 1728 |
ImageLength | |required
NewSubFileType | Bit 1 = 1 |single page of multipage file
PageNumber | X/X |pg/tot, 0 base, tot in 1st IFD
PhotometricInterp | 0 |0 is white
ResolutionUnit | 2 |inches (default)
RowsPerStrip |=ImageLength |
SamplesPerPixel | 1 |one sample per pixel
StripByteCounts | |required
StripOffsets | |required
T4Options | Bit 0 = 0 |MH
| Bit 1 = 0 |
| Bit 2 = 0,1 |Non-Byte-aligned,
| | Byte-Aligned EOLs
XResolution | 204 |Units is per inch
YResolution | 196,98 |Units is per inch
------------------|--------------|------------------------------
StripByteCounts | |required
StripOffsets | |required
T4Options | Bit 0 = 0 |MH
| Bit 1 = 0 |
| Bit 2 = 0,1 |Non-Byte-aligned,
| | Byte-Aligned EOLs
XResolution | 204 |Units is per inch
YResolution | 196,98 |Units is per inch
------------------|--------------|------------------------------
For implementations which need to write minimum subset TIFF-F files, the file structure shown in Figure 3.1 MUST be used:
对于需要写入最小子集TIFF-F文件的实现，必须使用图3.1所示的文件结构：
+-----------------------+
| Header |------------+
+-----------------------+ | First IFD
| IFD (page 0) | <----------+ Offset
+---| |------------+
| | |--+ |
Value | +-----------------------+ | |
Offset +-->| Long Values | | |
+-----------------------| | Strip |
| Image Data (page 0) |<-+ Offset |
+-----------------------+ | Next IFD
| IFD (page 1) | <----------+ Offset
+---| |------------+
| | |--+ |
Value | +-----------------------+ | |
Offset +-->| Long Values | | |
+-----------------------| | Strip |
| Image Data (page 1) |<-+ Offset |
+-----------------------+ | Next IFD
| IFD (page 2) | <----------+ Offset
+-----------------------+
| : |
| : |
+-----------------------+
| Header |------------+
+-----------------------+ | First IFD
| IFD (page 0) | <----------+ Offset
+---| |------------+
| | |--+ |
Value | +-----------------------+ | |
Offset +-->| Long Values | | |
+-----------------------| | Strip |
| Image Data (page 0) |<-+ Offset |
+-----------------------+ | Next IFD
| IFD (page 1) | <----------+ Offset
+---| |------------+
| | |--+ |
Value | +-----------------------+ | |
Offset +-->| Long Values | | |
+-----------------------| | Strip |
| Image Data (page 1) |<-+ Offset |
+-----------------------+ | Next IFD
| IFD (page 2) | <----------+ Offset
+-----------------------+
| : |
| : |
Figure 3.1 TIFF-F Minimum Subset File Structure
图3.1 TIFF-F最小子集文件结构
As depicted in Figure 3.1, the IFD of each page precedes the related Image Data for that page. If present, any long field values appear between the IFD and the image data for that page. For multiple page documents, each IFD/image pair is immediately followed by the next IFD/image pair in logical page order within the file structure, until all pages have been defined.
如图3.1所示，每个页面的IFD位于该页面的相关图像数据之前。如果存在，则IFD和该页面的图像数据之间会出现任何长字段值。对于多页文档，每个IFD/图像对后面紧跟着文件结构中的下一个IFD/图像对（按逻辑页面顺序），直到定义了所有页面。
The format for the TIFF Header is as defined in [TIFF]. When writing TIFF-F minimum subset files, the value for the byte order in the Header SHOULD be II (0x4949, denoting that the bytes in the TIFF file are in LSB first (little-endian) order.
TIFF标头的格式如[TIFF]中所定义。写入TIFF-F最小子集文件时，标头中的字节顺序值应为II（0x4949，表示TIFF文件中的字节以LSB优先（小端）顺序排列。
This results in a TIFF header whose content is as shown in Figure 3.2.
这将产生一个TIFF头，其内容如图3.2所示。
| Offset | Description | Type | Value |
+--------+-------------------+--------+--------------------+
| 0 | Byte Order | Short | 0x4949 (II) |
+--------+-------------------+--------+--------------------+
| 2 | Version | Short | 42 |
+--------+-------------------+--------+--------------------+
| 4 | Offset of 0th IFD | Long | 0x 0000 0008 |
+--------+-------------------+--------+--------------------+
| Offset | Description | Type | Value |
+--------+-------------------+--------+--------------------+
| 0 | Byte Order | Short | 0x4949 (II) |
+--------+-------------------+--------+--------------------+
| 2 | Version | Short | 42 |
+--------+-------------------+--------+--------------------+
| 4 | Offset of 0th IFD | Long | 0x 0000 0008 |
+--------+-------------------+--------+--------------------+
Figure 3.2: Image File Header for Minimum Subset TIFF-F Files
图3.2：最小子集TIFF-F文件的图像文件头
Those new to TIFF may not be familiar with the concept of "strips" embodied in the three fields RowsPerStrip, StripByteCount, StripOffsets.
TIFF新手可能不熟悉RowsPerStrip、StripByteCount和StripOffset三个字段中包含的“条带”概念。
In general, third-party implementations that read and write TIFF files expect the image to be divided into "strips," also known as "bands." Each strip contains a few lines of the image. By using strips, a TIFF reader need not load the entire image into memory, thus enabling it to fetch and decompress small random portions of the image as necessary.
通常，读取和写入TIFF文件的第三方实现希望将图像分为“条带”，也称为“条带”。每个条带包含几行图像。通过使用条带，TIFF阅读器无需将整个图像加载到内存中，从而使其能够根据需要提取和解压缩图像的随机小部分。
The dimensions of a strip are described by the RowsPerStrip and StripByteCount fields. The location in the TIFF file of each strip is contained in the StripOffsets field.
条带的尺寸由RowsPerStrip和StripByteCount字段描述。每个条带在TIFF文件中的位置包含在StripOffsets字段中。
The size of TIFF-F strips is application dependent. The recommended approach for multi-page TIFF-F images is to represent each page as a single strip.
TIFF-F条带的尺寸取决于应用。多页TIFF-F图像的推荐方法是将每一页表示为单个条带。
The default bit order in Baseline TIFF per [TIFF] is indicated by FillOrder=1, where bits are not reversed before being stored. However, TIFF-F typically utilizes the setting of FillOrder=2, where the bit order within bytes is reversed before storage (i.e., bits are stored with the Least Significant Bit first).
基线TIFF per[TIFF]中的默认位顺序由FillOrder=1表示，其中位在存储之前不会反转。然而，TIFF-F通常使用FillOrder=2的设置，其中字节内的位顺序在存储之前反转（即，位以最低有效位优先存储）。
Facsimile data appears on the phone line in bit-reversed order relative to its description in CCITT Recommendation T.4. Therefore, a wide majority of facsimile implementations choose this natural order for storage. Nevertheless, TIFF-F readers must be able to read data in both bit orders.
传真数据在电话线上的显示顺序与CCITT建议T.4中的描述相反。因此，大多数传真实现都选择这种自然的存储顺序。然而，TIFF-F读卡器必须能够以两种位顺序读取数据。
Many existing implementations already read TIFF-F like files, but do not support the multi- page field. Since a multi-page format greatly simplifies file management in fax application software, TIFF-F specifies multi-page documents (NewSubfileType = 2) as the standard case.
许多现有的实现已经读取了类似TIFF-F的文件，但不支持多页字段。由于多页格式大大简化了传真应用软件中的文件管理，TIFF-F将多页文档（NewSubfileType=2）指定为标准案例。
In Group 3 facsimile, there are three compression methods which had been standardized as of 1994 and are in common use. The ITU-T T.4 recommendation defines a one-dimensional compression method known as Modified Huffman (MH) and a two-dimensional method known as Modified READ (MR) (READ is short for Relative Element Address Designate). In 1984, a somewhat more efficient compression method known as Modified Modified READ (MMR) was defined in the T.6 recommendation. It was originally defined for use with Group 4 facsimile, so that this compression method has been commonly called Group 4 compression. In 1991, the MMR method was approved for use in Group 3 facsimile and has since been widely utilized.
在第3组传真中，有三种压缩方法，自1994年起已被标准化，并普遍使用。ITU-T T.4建议定义了一种称为修改的哈夫曼（MH）的一维压缩方法和一种称为修改的读取（MR）的二维方法（读取是相对元素地址指定的缩写）。1984年，T.6建议中定义了一种更有效的压缩方法，称为修改读取（MMR）。它最初定义用于第4组传真，因此这种压缩方法通常被称为第4组压缩。1991年，MMR方法被批准用于第3组传真，并已被广泛使用。
TIFF-F permits three different compression methods. In the most common practice, the one-dimensional compression method (Modified Huffman) is used. This is specified by setting the value of the Compression field to 3 and then setting bit 0 of the T4Options field to 0. Alternatively, the two dimensional Modified READ method (which is much less frequently used in historical TIFF-F implementations) may be selected by setting bit 0 to a value of 1.
TIFF-F允许三种不同的压缩方法。在最常见的实践中，使用一维压缩方法（修改的哈夫曼）。这是通过将压缩字段的值设置为3，然后将T4Options字段的位0设置为0来指定的。或者，可以通过将位0设置为值1来选择二维修改读取方法（在历史TIFF-F实现中使用频率要低得多）。
Optionally, depending upon the implementation requirements, the more efficient two-dimensional compression method from T.6 (i.e. MMR or "Group 4 compression") may be selected. This method is selected by
可选地，根据实施要求，可以选择来自T.6的更有效的二维压缩方法（即MMR或“第4组压缩”）。此方法由以下人员选择：
setting the value of the Compression field to 4 and then setting the value of the first two bits (and all unused bits) of T6options to 0. More information to aid the implementer in making a compression selection is contained in section 3.8 on Implementation Warnings.
将压缩字段的值设置为4，然后将T6options的前两位（以及所有未使用位）的值设置为0。关于实现警告的第3.8节中包含了帮助实现者进行压缩选择的更多信息。
Here are examples for writing the CleanFaxData, BadFaxLines, and ConsecutiveBadFaxLines fields:
以下是写入CleanFaxData、BadFaxLines和ConcertiveBadFaxLines字段的示例：
1. Facsimile hardware does not provide page quality information: MUST NOT write page-quality fields. 2. Facsimile hardware provides page quality information, but reports no bad lines. Write only BadFaxLines = 0. 3. Facsimile hardware provides page quality information, and reports bad lines. Write both BadFaxLines and ConsecutiveBadFaxLines. Also write CleanFaxData = 1 or 2 if the hardware's regeneration capability is known. 4. Source image data stream is error-corrected or otherwise guaranteed to be error-free such as for a computer generated file: SHOULD NOT write page-quality fields.
1. 传真硬件不提供页面质量信息：不得写入页面质量字段。2.传真硬件提供页面质量信息，但不报告坏行。只写BadFaxLines=0。3.传真硬件提供页面质量信息，并报告错误行。写入错误传真行和连续错误传真行。如果已知硬件的再生能力，还可以写入CleanFaxData=1或2。4.源图像数据流已更正错误或以其他方式保证无错误，例如计算机生成的文件：不应写入页面质量字段。
TIFF-F has historically been used for handling fax image files in implementations such as store and forward messaging where the entire size of the file is known in advance. While TIFF-F may also possibly be used as a file format for cases such as streaming applications, different assumptions may be required than those provided in this document (e.g., the entire size and number of pages within the image are not known in advance). As a result, a definition for the streaming application of TIFF-F is beyond the scope of this document.
TIFF-F历来用于处理传真图像文件，例如存储和转发消息传递，其中文件的整个大小是事先已知的。虽然TIFF-F也可能用作流媒体应用程序等情况下的文件格式，但可能需要不同于本文档中提供的假设（例如，图像中的整个大小和页数事先未知）。因此，TIFF-F流媒体应用的定义超出了本文档的范围。
Fax implementations that do not wish to support TIFF-F as a native format may elect to support it as import/export medium.
不希望支持TIFF-F作为本机格式的传真实现可以选择支持TIFF-F作为导入/导出介质。
Export
出口
It is recommended that implementations export multiple page TIFF-F files without manipulating fields and values. Historically, some TIFF-F writers have attempted to produce individual single-page TIFF-F files with modified NewSubFileType and PageNumber (page one-of-one) values for export purposes. However, there is no easy way to link such multiple single page files together into a logical multiple page document, so that this practice is not recommended.
建议实现在不操纵字段和值的情况下导出多页TIFF-F文件。从历史上看，一些TIFF-F编写器曾尝试使用修改过的NewSubFileType和PageNumber（第一页，共一页）值生成单个单页TIFF-F文件，以用于导出目的。但是，没有简单的方法将多个单页文件链接到一个逻辑多页文档中，因此不建议采用这种做法。
Import
进口
A TIFF-F reader MUST be able to handle a TIFF-F file containing multiple pages.
TIFF-F阅读器必须能够处理包含多个页面的TIFF-F文件。
3.8.1 Uncompressed data
3.8.1 未压缩数据
TIFF-F requires the ability to read and write at least one-dimensional T.4 Huffman ("compressed") data. Uncompressed data is not allowed. This means that the "Uncompressed" bit in T4Options or T6Options must be set to 0.
TIFF-F要求能够读取和写入至少一维T.4 Huffman（“压缩”）数据。不允许使用未压缩的数据。这意味着T4Options或T6Options中的“未压缩”位必须设置为0。
Since two-dimensional encoding is not required for Group 3 compatibility, some historic TIFF-F readers have not been able to read such files. The minimum subset of TIFF-F REQUIRES support for one dimensional (Modified Huffman) files, so this choice maximizes portability. However, implementers seeking greater efficiency SHOULD use T.6 MMR compression when writing TIFF-F files. Some TIFF-F readers will also support two-dimensional Modified READ files. Implementers that wish to have the maximum flexibility in reading TIFF-F files SHOULD support all three of these compression methods (MH, MR and MMR).
由于第3组兼容性不需要二维编码，因此一些历史上的TIFF-F阅读器无法读取此类文件。TIFF-F的最小子集要求支持一维（修改过的Huffman）文件，因此这种选择最大限度地提高了可移植性。但是，寻求更高效率的实现者在编写TIFF-F文件时应使用T.6 MMR压缩。一些TIFF-F阅读器还支持二维修改读取文件。希望在读取TIFF-F文件时具有最大灵活性的实现者应该支持这三种压缩方法（MH、MR和MMR）。
For the case of resolution, almost all facsimile products support both standard (98 dpi) vertical resolution and "fine" (196 dpi) resolution. Therefore, fine-resolution files are quite portable in the real world.
就分辨率而言，几乎所有传真产品都支持标准（98 dpi）垂直分辨率和“精细”（196 dpi）分辨率。因此，高分辨率文件在现实世界中是非常可移植的。
In 1993, the ITU-T added support for higher resolutions in the T.30 recommendation including 200 x 200, 300 x 300, 400 x 400 in dots per inch based units. At the same time, support was added for metric dimensions which are equivalent to the following inch based resolutions: 391v x 204h and 391v x 408h. Therefore, the full set of inch-based equivalents of the new resolutions are supported in the TIFF-F writer, since they may appear in some image data streams received from Group 3 facsimile devices. However, many facsimile terminals and older versions of TIFF-F readers are likely to not support the use of these higher resolutions.
1993年，ITU-T在T.30建议中增加了对更高分辨率的支持，包括每英寸200 x 200、300 x 300、400 x 400点的单位。同时，增加了对公制尺寸的支持，这些尺寸相当于以下基于英寸的分辨率：391v x 204h和391v x 408h。因此，TIFF-F writer支持新分辨率的全套基于英寸的等效图像，因为它们可能出现在从第3组传真设备接收的一些图像数据流中。然而，许多传真终端和旧版本的TIFF-F阅读器可能不支持使用这些更高分辨率。
Per [T.4], it is permissible for implementations to treat the
following XResolution values as being equivalent: <204,200> and
<400,408>. In a similar respect, the following YResolution values
Per [T.4], it is permissible for implementations to treat the
following XResolution values as being equivalent: <204,200> and
<400,408>. In a similar respect, the following YResolution values
may also be treated as being equivalent: <98, 100>, <196, 200>, and <391, 400>. These equivalencies were allowed by [T.4] to permit conversions between inch and metric based facsimile terminals.
也可被视为等效：<98100>、<196200>和<391400>。[T.4]允许这些等效性，以允许在基于英寸和公制的传真终端之间进行转换。
In a similar respect, the optional support of metric based resolutions in the TIFF-F reader (i.e. 77 x 38.5 cm) is included for completeness, since they are used in some legacy TIFF-F implementations, but this use is not recommended for the creation of TIFF-F files by a writer.
在类似方面，TIFF-F阅读器（即77 x 38.5 cm）中可选支持基于度量的分辨率是为了完整性，因为它们在一些传统TIFF-F实现中使用，但不建议写入者在创建TIFF-F文件时使用。
The historical convention for TIFF-F has been that all EOLs in Modified Huffman or Modified READ data must be byte-aligned. However, Baseline TIFF has permitted use of non-byte-aligned EOLs by default, so that a large percentage of TIFF-F reader implementations support both conventions. Therefore, the minimum subset of TIFF-F as defined in this document includes support for both byte-aligned and non-byte-aligned EOLs.
TIFF-F的历史惯例是，修改后的Huffman或修改后的读取数据中的所有EOL必须是字节对齐的。但是，基线TIFF默认情况下允许使用非字节对齐的EOL，因此大部分TIFF-F读卡器实现都支持这两种约定。因此，本文档中定义的TIFF-F的最小子集包括对字节对齐和非字节对齐EOL的支持。
An EOL is said to be byte-aligned when Fill bits have been added as necessary before EOL codes such that EOL always ends on a byte boundary, thus ensuring an EOL-sequence of a one byte preceded by a zero nibble: xxxx0000 00000001.
当在下线代码之前根据需要添加填充位时，下线被称为字节对齐，这样下线总是在字节边界上结束，从而确保下线序列的前半字节为一个字节：xxxx0000 0000000 1。
Modified Huffman encoding encodes bits, not bytes. This means that the end-of-line token may end in the middle of a byte. In byte alignment, extra zero bits (Fill) are added so that the first bit of data following an EOL begins on a byte boundary. In effect, byte alignment relieves application software of the burden of bit-shifting every byte while parsing scan lines for line-oriented image manipulation (such as writing a TIFF file).
修改的哈夫曼编码编码位，而不是字节。这意味着行尾令牌可以在字节中间结束。在字节对齐中，添加额外的零位（填充），以便下线后的第一位数据从字节边界开始。实际上，字节对齐减轻了应用软件在解析扫描行以进行面向行的图像处理（如编写TIFF文件）时对每个字节进行位移位的负担。
For Modified READ encoding, each line is terminated by an EOL and a one bit tag bit. Per [T.4], the value of the tag bit is 0 if the next line contains two dimensional data and 1 if the next line is a reference line. To maintain byte alignment, fill bits are added before the EOL/tag bit sequence, so that the first bit of data following an MR tag bit begins on a byte boundary.
对于修改的读取编码，每行由一个EOL和一位标记位终止。根据[T.4]，如果下一行包含二维数据，则标记位的值为0，如果下一行是参考线，则标记位的值为1。为了保持字节对齐，在下线/标记位序列之前添加填充位，以便MR标记位之后的第一位数据从字节边界开始。
As illustrated in FIGURE 1/T.4 in [T.4], facsimile documents encoded with Modified Huffman begin with an EOL (which in TIFF-F may be byte-aligned). The last line of the image is not terminated by an EOL. In a similar respect, images encoded with Modified READ two dimensional encoding begin with an EOL, followed by a tag bit.
如[T.4]中图1/T.4所示，使用修改后的哈夫曼编码的传真文件以EOL开头（在TIFF-F中，EOL可以是字节对齐的）。图像的最后一行不是由下线终止的。在类似的方面，使用修改的读取二维编码编码的图像以EOL开始，然后是标记位。
Aside from EOLs, TIFF-F files have historically only contained image data. This means that implementations which wish to maintain strict conformance with the rules in [TIFF] and compatibility with historical TIFF-F, SHOULD NOT include the Return To Control sequence (RTC) (consisting of 6 consecutive EOLs) when writing TIFF- F files. However, implementations which need to support "transparency" of [T.4] image data MAY include RTCs when writing TIFF-F files if the flag settings of the T4Options field are set for non-byte aligned MH or MR image data. Implementors of TIFF readers should also be aware that there are some existing TIFF-F implementations which include the RTC sequence in MH/MR image data. Therefore, TIFF-F readers MUST be able to process files which do not include RTCs and SHOULD be able to process files which do include RTCs.
除了EOL，TIFF-F文件历史上只包含图像数据。这意味着，在编写TIFF-F文件时，希望严格遵守[TIFF]中的规则并与历史TIFF-F兼容的实施不应包括返回控制序列（RTC）（由6个连续EOL组成）。但是，如果为非字节对齐的MH或MR图像数据设置了T4Options字段的标志设置，则在写入TIFF-F文件时，需要支持[T.4]图像数据“透明”的实现可能包括RTC。TIFF阅读器的实现者还应该知道，一些现有的TIFF-F实现包括MH/MR图像数据中的RTC序列。因此，TIFF-F阅读器必须能够处理不包含RTC的文件，并且应该能够处理包含RTC的文件。
TIFF-F pages which are encoded with the T.6 Modified Modified READ compression method MUST include an "end-of-facsimile-block" (EOFB) code at the end of each coded strip. Per [TIFF], the EOFB code is followed by pad bits as needed to align on a byte boundary. TIFF readers SHOULD ignore any bits other than pad bits beyond the EOFB.
使用T.6修改读取压缩方法编码的TIFF-F页面必须在每个编码条的末端包含“传真块结束”（EOFB）代码。根据[TIFF]，EOFB代码后面跟着根据需要在字节边界上对齐的焊盘位。TIFF读取器应忽略除EOFB之外的pad位以外的任何位。
Implementations may choose to implement a TIFF-F Reader, TIFF-F Writer or both, depending upon application requirements. The TIFF- F Reader is typically used to read an existing TIFF-F file which resides on a computer or peripheral device. The TIFF-F Writer is typically used to convert a bi-level image bit stream into a TIFF-F compliant file. For many Internet applications, only the Reader needs to be implemented. The specific field support required for TIFF-F Readers and Writers is summarized below.
根据应用要求，实现可能选择实现TIFF-F读卡器、TIFF-F写卡器或两者兼有。TIFF-F读取器通常用于读取驻留在计算机或外围设备上的现有TIFF-F文件。TIFF-F Writer通常用于将双层图像位流转换为符合TIFF-F的文件。对于许多Internet应用程序，只需要实现读卡器。TIFF-F读写器所需的特定现场支持概述如下。
The fields in the following table are specified for a TIFF-F Reader. The range of values for required and recommended fields are as shown. The minimum subset of values are also shown. If required fields are omitted in a TIFF-F file, the Baseline TIFF default value will apply. Image data must not have any coding errors. In the table, certain fields have a value that is a sequence of flag bits (e.g. T4Options). An implementation should test the setting of the relevant flag bits individually to allow extensions to the sequence of flag bits to be appropriately ignored.
下表中的字段是为TIFF-F读取器指定的。必填字段和推荐字段的值范围如图所示。还显示了值的最小子集。如果TIFF-F文件中省略了必填字段，则将应用基线TIFF默认值。图像数据不得有任何编码错误。在表中，某些字段的值是一系列标志位（例如T4Options）。实现应单独测试相关标志位的设置，以允许适当忽略标志位序列的扩展。
As noted within [TIFF], a TIFF file begins with an 8-byte image file header, of which the first two bytes (0-1) contain the byte order within the file. The permissible values are:
如[TIFF]中所述，TIFF文件以8字节的图像文件头开头，其中前两个字节（0-1）包含文件中的字节顺序。允许值为：
II- Byte order from least significant byte to the most significant byte (little-endian) MM - byte order is always from most significant to least significant (big-endian)
II-字节顺序从最低有效字节到最高有效字节（小尾端）MM-字节顺序始终从最高有效字节到最低有效字节（大尾端）
For a TIFF-F Reader, the legal values are:
对于TIFF-F阅读器，其法律价值为：
ByteOrder: MM,II (Either byte order is allowed)
字节顺序：MM，II（允许任意一个字节顺序）
Recommended Fields in the table are shown with an asterisk (*).
表中的推荐字段以星号（*）显示。
Other fields may be present, but they should be of an informational nature, so that a reader can elect to ignore them.
可能存在其他字段，但它们应具有信息性质，以便读者可以选择忽略它们。
Informational fields which are often present in TIFF-F images are: Software, Datetime, BadFaxLines, CleanFaxData and ConsecutiveBadFaxLines.
TIFF-F图像中经常出现的信息字段有：软件、日期时间、无效传真线、CleanFaxData和连续无效传真线。
Field | Values | Minimum | Comment
------------------|-------------|-------------|----------------------
BitsPerSample | 1 | 1 |one bit per sample
Compression | 3,4 | 3 |3 for T.4 (MH, MR)
| | |4 for T.6 - MMR
FillOrder | 2,1 | 2 |LSB first or MSB first
ImageWidth | 1728, 2048, | 1728 |depends on XResolution
| 2432, 2592, | |
| 3072, 3648, | |
| 3456, 4096, | |
| 4864 | |
ImageLength | >0 | |required
NewSubFileType | Bit 1 = 1 | Bit 1 = 1 |single page of
| | |multipage file
Orientation * | 1 | |1st row=top left,
| | | 1st col=top
PageNumber | X/X | 0/1 |pg/tot, 0 base,
| | | tot in 1st IFD
PhotometricInterp | 0,1 | 0 |0 is white
ResolutionUnit | 2,3 | 2 |inches (default)
RowsPerStrip |=ImageLength |=ImageLength |
| or other | |
SamplesPerPixel | 1 | 1 |one sample per pixel
StripByteCounts | >0 | |required
Field | Values | Minimum | Comment
------------------|-------------|-------------|----------------------
BitsPerSample | 1 | 1 |one bit per sample
Compression | 3,4 | 3 |3 for T.4 (MH, MR)
| | |4 for T.6 - MMR
FillOrder | 2,1 | 2 |LSB first or MSB first
ImageWidth | 1728, 2048, | 1728 |depends on XResolution
| 2432, 2592, | |
| 3072, 3648, | |
| 3456, 4096, | |
| 4864 | |
ImageLength | >0 | |required
NewSubFileType | Bit 1 = 1 | Bit 1 = 1 |single page of
| | |multipage file
Orientation * | 1 | |1st row=top left,
| | | 1st col=top
PageNumber | X/X | 0/1 |pg/tot, 0 base,
| | | tot in 1st IFD
PhotometricInterp | 0,1 | 0 |0 is white
ResolutionUnit | 2,3 | 2 |inches (default)
RowsPerStrip |=ImageLength |=ImageLength |
| or other | |
SamplesPerPixel | 1 | 1 |one sample per pixel
StripByteCounts | >0 | |required
StripOffsets | >0 | |required
T4Options | Bit 0 = 0,1 | Bit 0 = 0 |MH,MR(incl if not MMR)
| Bit 1 = 0 | Bit 1 = 0 |
| Bit 2 = 0,1 | Bit 2 = 0,1 | Non-Byte-aligned and
| | | Byte-Aligned EOLs
T6Options | 0 | |MMR (incl only if MMR)
XResolution | 204,200,300,| 204 | If unit is per inch
| 400,408, | |
| 77 | | If unit is per cm
YResolution | 196,98,100, | 196,98 | If unit is per inch
| 200,300,391,| |
| 400, | |
| 77,38.5 | | If unit is per cm
------------------|-------------|-------------|----------------------
StripOffsets | >0 | |required
T4Options | Bit 0 = 0,1 | Bit 0 = 0 |MH,MR(incl if not MMR)
| Bit 1 = 0 | Bit 1 = 0 |
| Bit 2 = 0,1 | Bit 2 = 0,1 | Non-Byte-aligned and
| | | Byte-Aligned EOLs
T6Options | 0 | |MMR (incl only if MMR)
XResolution | 204,200,300,| 204 | If unit is per inch
| 400,408, | |
| 77 | | If unit is per cm
YResolution | 196,98,100, | 196,98 | If unit is per inch
| 200,300,391,| |
| 400, | |
| 77,38.5 | | If unit is per cm
------------------|-------------|-------------|----------------------
For the case of writing (creating) a TIFF-F file format from an image data stream or other raster data, implementations SHOULD write files which can be read by a TIFF-F Reader as defined in 3.9.1. It is recommended that all fields from the table in 3.9.1.1 SHOULD be included when writing TIFF-F files in order to minimize dependencies on default values. Image data must not have any coding errors.
对于从图像数据流或其他光栅数据写入（创建）TIFF-F文件格式的情况，实施应写入可由TIFF-F读取器读取的文件，如3.9.1所述。建议在写入TIFF-F文件时，应包括3.9.1.1中表格中的所有字段，以尽量减少对默认值的依赖性。图像数据不得有任何编码错误。
Other fields may be present, but they should be of an informational nature, so that a Reader may elect to ignore them.
可能存在其他字段，但它们应具有信息性质，以便读者可以选择忽略它们。
For the case of writing "minimum subset" TIFF-F files, the rules defined in section 3.6 apply.
对于编写“最小子集”TIFF-F文件的情况，第3.6节中定义的规则适用。
Informational fields that may be useful for TIFF-F files are: Software, Datetime, BadFaxLines, ConsecutiveBadFaxLines
可能对TIFF-F文件有用的信息字段有：软件、日期时间、无效传真线、连续无效传真线
TIFF Writers SHOULD only generate the fields that describe facsimile image quality when the image has been generated from a fax image data stream where error correction (e.g. Group 3 Error Correction Mode) was not used. These fields are: CleanFaxData, BadFaxLines and ConsecutiveBadFaxLines.
当图像是从没有使用纠错（例如第3组纠错模式）的传真图像数据流生成时，TIFF写入程序应仅生成描述传真图像质量的字段。这些字段是：CleanFaxData、BadFaxLines和ConcertiveBadFaxLines。
[TIFFREG] describes the registration of the MIME content-type image/ tiff to refer to TIFF 6.0 encoded image data. When transported by MIME, the TIFF content defined by this document must be encoded within an image/tiff content type. In addition, an optional "application" parameter is defined for image/tiff to identify a particular application's subset of TIFF and TIFF extensions for the
[TIFFREG]描述MIME内容类型图像/tiff的注册，以引用tiff 6.0编码图像数据。通过MIME传输时，此文档定义的TIFF内容必须在图像/TIFF内容类型中进行编码。此外，还为image/tiff定义了一个可选的“application”参数，以标识特定应用程序的tiff子集和应用程序的tiff扩展
encoded image data, if it is known. Typically, this would be used to assist the recipient in dispatching a suitable rendering package to handle the display or processing of the image file.
编码图像数据（如果已知）。通常，这将用于帮助接收者分派适当的渲染包来处理图像文件的显示或处理。
Since this document defines a facsimile specific profile of TIFF, it is useful to note an appropriate application parameter for the image/tiff MIME content-type.
由于本文档定义了TIFF的传真特定配置文件，因此请注意图像/TIFF MIME内容类型的适当应用程序参数。
The "faxbw" application parameter is defined for black and white facsimile. It is suitable for use by applications that can process one or more TIFF for facsimile profiles or subsets used for the encoding of black and white facsimile data.
“faxbw”应用程序参数是为黑白传真定义的。它适用于可处理传真配置文件的一个或多个TIFF或用于黑白传真数据编码的子集的应用程序。
Since this document defines a profile of TIFF for facsimile which is suitable for use with black and white facsimile image data, applications which use this profile or its minimum subset should set the value of the application parameter to "faxbw".
由于本文档定义了适用于黑白传真图像数据的传真TIFF配置文件，因此使用此配置文件或其最小子集的应用程序应将应用程序参数的值设置为“faxbw”。
An example of the use of the image/tiff MIME Content-type with the application parameter set with the value "faxbw" follows:
使用image/tiff MIME内容类型并将应用程序参数设置为值“faxbw”的示例如下：
Example:
例子：
Content-type: image/tiff; application=faxbw
Content-type: image/tiff; application=faxbw
In this example, use of this parameter value will enable applications to identify the content as being within a profile or subset of TIFF for Facsimile that is suitable for encoding black and white image data, before attempting to process the image data.
在此示例中，使用此参数值将使应用程序能够在尝试处理图像数据之前，将内容识别为在适于编码黑白图像数据的传真用TIFF的简档或子集内。
5.1 Internet Fax Usage
5.1 互联网传真的使用
The usage of TIFF-F is envisioned as a component of Internet Fax. It is anticipated that Internet Fax may use both a TIFF-F Reader and TIFF-F Writer. The details of the Internet Fax services and their use of TIFF-F will be specified in other documents.
TIFF-F的使用被设想为互联网传真的一个组成部分。预计互联网传真可能同时使用TIFF-F阅读器和TIFF-F书写器。互联网传真服务及其使用TIFF-F的详细信息将在其他文件中规定。
The Application F of TIFF (i.e. TIFF-F content) is a secondary component of the VPIM Message as defined in [VPIM2]. Voice messaging systems can often handle fax store-and-forward capabilities in addition to traditional voice message store-and- forward functions.
TIFF的应用程序F（即TIFF-F内容）是[VPIM2]中定义的VPIM消息的次要组件。除了传统的语音信息存储和转发功能外，语音信息系统通常还可以处理传真存储和转发功能。
As a result, TIFF-F fax messages can optionally be sent between compliant VPIM systems, and may be rejected if the recipient system cannot deal with fax.
因此，TIFF-F传真消息可以选择在兼容的VPIM系统之间发送，如果收件人系统无法处理传真，则可能会被拒绝。
Refer to the VPIM Specification for proper usage of this content.
有关此内容的正确用法，请参阅VPIM规范。
This document describes the encoding for TIFF-F, which is a profile of the TIFF encoding for facsimile. As such, it does not create any security issues not already identified in [TIFFREG], in its use of fields as defined in [TIFF]. There are also new TIFF fields defined within this specification, but they are of a purely descriptive nature, so that no new security risks are incurred.
本文档描述了TIFF-F的编码，它是传真TIFF编码的一个概要文件。因此，在使用[TIFF]中定义的字段时，不会产生[TIFFREG]中未发现的任何安全问题。本规范中还定义了新的TIFF字段，但它们是纯描述性的，因此不会产生新的安全风险。
Further, the encoding specified in this document does not in any way preclude the use of any Internet security protocol to encrypt, authenticate, or non-repudiate TIFF-F encoded facsimile messages.
此外，本文件中规定的编码并不以任何方式排除使用任何互联网安全协议对TIFF-F编码传真消息进行加密、认证或不可否认性。
Glenn W. Parsons Northern Telecom P.O. Box 3511, Station C Ottawa, ON K1Y 4H7 Canada Phone: +1-613-763-7582 Fax: +1-613-763-2697 Email: Glenn.Parsons@Nortel.ca
Glenn W.Parsons Northern Telecom邮政信箱3511，渥太华C站，电话：K1Y 4H7加拿大电话：+1-613-763-7582传真：+1-613-763-2697电子邮件：Glenn。Parsons@Nortel.ca
James Rafferty Human Communications 12 Kevin Drive Danbury, CT 06811-2901 USA Phone: +1-203-746-4367 Fax: +1-203-746-4367 Email: Jrafferty@worldnet.att.net
詹姆斯·拉弗蒂人类通信公司美国康涅狄格州丹伯里凯文大道12号06811-2901电话：+1-203-746-4367传真：+1-203-746-4367电子邮件：Jrafferty@worldnet.att.net
[MIME1] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [MIME4] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, November 1996.
[MIME1]Freed，N.和N.Borenstein，“多用途Internet邮件扩展（MIME）第一部分：Internet邮件正文格式”，RFC 20451996年11月。[MIME4]Freed，N.和N.Borenstein，“多用途互联网邮件扩展（MIME）第四部分：注册程序”，RFC 20481996年11月。
[REQ] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[T.30] ITU-T Recommendation T.30 - "Procedures for Document
Facsimile Transmission in the General Switched Telephone
Network", June, 1996
[T.4] ITU-T Recommendation T.4 - "Standardization of Group 3
Facsimile Apparatus for Document Transmission", June, 1996
[T.6] ITU-T Recommendation T.6 - "Facsimile Coding Schemes and
Coding Control Functions for Group 4 Facsimile Apparatus",
March, 1993
[TIFF] Adobe Developers Association, TIFF (TM) Revision 6.0 -
Final, June 3, 1992.
[TIFFREG] Parsons, G., Rafferty, J. and S. Zilles, "Tag Image File
Format (TIFF) - image/tiff: MIME Sub-type Registration ", RFC
2302, March 1998.
[VPIM2] G. Vaudreuil and G. Parsons, "Voice Profile for Internet
Mail - version 2", Work In Progress, <draft-ema-vpim-06.txt>,
November 1997.
[REQ] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[T.30] ITU-T Recommendation T.30 - "Procedures for Document
Facsimile Transmission in the General Switched Telephone
Network", June, 1996
[T.4] ITU-T Recommendation T.4 - "Standardization of Group 3
Facsimile Apparatus for Document Transmission", June, 1996
[T.6] ITU-T Recommendation T.6 - "Facsimile Coding Schemes and
Coding Control Functions for Group 4 Facsimile Apparatus",
March, 1993
[TIFF] Adobe Developers Association, TIFF (TM) Revision 6.0 -
Final, June 3, 1992.
[TIFFREG] Parsons, G., Rafferty, J. and S. Zilles, "Tag Image File
Format (TIFF) - image/tiff: MIME Sub-type Registration ", RFC
2302, March 1998.
[VPIM2] G. Vaudreuil and G. Parsons, "Voice Profile for Internet
Mail - version 2", Work In Progress, <draft-ema-vpim-06.txt>,
November 1997.
Copyright (C) The Internet Society (1998). All Rights Reserved.
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上述授予的有限许可是永久性的，互联网协会或其继承人或受让人不会撤销。
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